Apparatus for testing expansion of movable members



May 26, 1959 M.- FRANKEL ETAL v APPARATUS FOR TES'TING EXPANSION OF MOVABLE MEMBERS Filed July 2. 1947 United States Patent if 2,381,876 APPARATUS non' TESTING EXPANSION oF 1 MovAnLE l Melvin Frankel and Walter Bradford Shank, Los Angeles, Calif., assignors to the United States of America as represented by the United States Atomic Energy rCommission Application July 2, 1947, Serial No. 758,498

4 Claims. (Cl. 73-52) means for moving the member Within its container and for Y Y measuring the frictional resistance between the member andthe container by measuring the lforce under which the member moves.

The invention is particularly well suited to a neutronic reactor of the type employing cylindrical cartridges of 'ssionable material called slug/s, for detecting swelling inl faulty slugs before damage is caused to the reactor. Thus another object of the invention is to'provide a novel means for detecting faulty slugs in a neutronic reactor.

' The foregoing and other objects and advantages of the invention will become apparent from a consideration of the following specification and the accompanying drawings, wherein:

Fig. y1 is a fragmentary central vertical cross sectional View partly in elevation of a device embodying the invention, in combination With a diagram illustrating a novel hydraulic system for actuating the device; and

Fig. 2 is a cross sectional View taken in the vertica plane lindicated by the line 2 2 of Fig. l.

The invention is illustrated as applied to a neutronic reactor generally designated 2 and comprising a mass 4 of neutron moderator such as graphite or beryllium. A tube 6 of neutron-permeable material having a relatively small neutron capture cross-section, such as, for example, aluminum or beryllium, extends through-the moderator mass 4 and contains a plurality of aluminum-jacketed uranium slugs 8 disposed end-to-end extending through the moderator mass 4. One of the slugs B in Fig. l is illustrated partially in central Vertical cross-section.

It will be understood that in lactual practice a great number :oftubes 6 containing slugs 8 arel disposed within the moderator mass 4 to provide a reactive composition capable of sustaining a nuclear fission chain reaction. As azresult of the nuclear fission chain reaction, considerable heat` is'developed Within the slugs 8, and this heat is dissipated by a coolant, such as water, passed through the tube 6 by inlet and outlet conduits 10 and 12 connected .to `the tubeby iittings 14 and 16, respectively. As will v same to become xed within the tube 6, thus preventingA ICG' removal of the slugstherefrom as is necessary from time to time to renew the slugs and recover products of the' nuclear reaction.` Furthermore, swelling of the slug may continue, blocking flow of Water through thel annulus` 20, thereby preventing cooling of the other slugs within the tube and causing excessive heating.

Thus, it Will be Vunderstood that in a system such as: above described it is very important to determine fromtime to' time whether any of the slugs 8 within the tub-e 6 have swelled. This determination is made by the novel apparatus disclosed in Fig.A 1, said apparatus comprising cylinders 22 and 24 secured to opposite ends ofI the tube 6 by fittings 26 and 27, respectively. Thefcylinder 24 at the coolant inlet end of the tube contains a hollow piston 2S which is actuated by hydraulic uid admittedy to the l' cylinder 24 through a line 3 0. A plunger 34 is slidably tted vwithin the piston 28 in threaded engagement'therewith as at 36, the outer end of the plunger being provided with a lock nut 38. Thus, it willbe understood that by` l; lrotating the plunger 34, it may be adjusted relative to the i piston 28 Iso that it properly bears against the row of slugs 8, For the latter purpose, there are likewise pro? vided spacers 37 and 39, for example of stainless steel.

The cylinder 22 at the coolant outlet end of the tube v l6 contains a piston 40 which isv integrally formed withva facilitates measurement ofthe force necessary to move, the slugs by measurement of the pressurein a common b'e'clea'rly seen in Fig. 2, the tube 6 is provided with a plurality of longitudinal ribs 18 which bear against the slugs 8 to center the same within the tube, thereby affording an annulus 20 around the slugs to accommodate ow of the coolant, such as Water, which is circulated as above described by means of inlet and outlet conduits 10 and 12.

It will be understood that leakage of the water through one of the slug jackets causes the same to expand inasmuch as the water reacts with the uranium to form uranium oxide which has a greater specific volume than metal. This swelling of the slug 8 may cause the plunger 41bearing against the adjacent slug 8, said piston being actuated by hydraulic fluid admittedv to the cylnder 22 by a line 42. y

, Thus, it will be understood that the row of slugs 8 is pushed back and forth Within the tube 46 by means oflthe plungers 34 and 41, the plunger'41 having a relatively great diameter so that the total pressure exerted against the respective plungers by the coolant is approximately equal, inasmuch as the coolant pressure at the inlet end ofthe tube is greater than at the outlet end thereof; This fluid supply line adapted to be alternatelyl connected to the cylinders22 and 24 as hereinafter discussed. As the slugs 8 are moved back and forth within the tube 6, yswelling of any slug within the tube increases lthe resistance ofv` the slugs to the Iforce exerted thereagainst and is detected by measurement of that resistance.

The resistance to movement` of the slugs by the develg.

opment of friction between a swollen slug and the tube is me'asured'as hereinafter described by the hydraulicvac-Ir tuation circuit associated with the cylinders 22 and 24. n This circuit comprises a reservoir 46 containing a supply of any suitable hydraulic medium such as oil, said reservoir being connected by a line 48 to the suction side' of a pump 50, the discharge sideof which is connected to a" supply line 52`having a surge'tank 54 therein for therpul-,

pose of compensating for minor variations inthe pressure. y exerted by the pump 50. The line 48 is provided` with a one-waycheck valve56 accommodating iow of fluid to p the pun1p 50 and` is also provided with adrain valve',5,8 f for draining the system. The line 52 is provided withY Vai.' drain valve 60,( and is connected to arelief or discharge line A6,2: through ay throttle valve` in 'the formtof ai 4contfg ventinal needle valve 64." Thus', by adjusting the'throttle" valve 64, a predetermined value is built up Within the main supply line 52, said value being measured by a gauge 66 connected to the line 52 by a throttle valve 68 which is closed slightly, so that the valve 68 functions as a snubber to prevent violent movement of the gauge needle which might result in damage to the gauge. 'I'he line 52 is also connected through a conventional relief valve 70 to the before-mentioned discharge line 62, said valve 70 being adapted to open the line 52 to discharge upon the development therein of a predetermined maximum safe pressure value.

The line 52 is connected through a throttle valve 72 to a branch line 74 which is connected to a conventional three-position selector valve 76 adapted to selectively open the line 74 to communication with one of the lines 30"and 42 associated respectively with the cylinders 24 and 22 as heretofore described or, in the third or neutral position, to mutually interconnect the lines 74, 30, 42 and 62. The branch line 74 is provided` with a surge tank 78 and a gauge 80 connected to the line 74 through a throttle valve S2 functioning as a snubberfin the manner described in connection with the valve 68. The line 74 is also connected to the line 62 through a throttle valve 84 accommodating adjustment of pressure within the branch line 74 as hereinafter described.

It will be seen that the line 52, shown as heavy piping in Fig. 1, constitutes a constant high pressure portion of the system. The line 62 constitutes a discharge line which is always substantially at atmospheric pressure. The line 74 contains uicl which is made to vary in pressure from atmospheric pressure up to the constant pressure of the line 52. Operation of the device, other than preliminary adjustment, is accomplished by operation of the valve 76, all other valves being held in fixed position during operation. The valve 64 serves as an adjustment of the constant pressure in the line 52. This is so adjusted that the constant pressure in the line 52, as indicated by the gauge 66, is a suitable amount, for example 30to 50 pounds per square inch, greater than the pressure required lto move the row of slugs 8 against the frictional forces which are present in they absence of swelling on any of the slugs 8. When the valve 76 is in the neutral position, the lines 74, 30 and 42 are all` substantially at atmospheric pressure. In this position, the total pressure drop between the constant pressure line 52 and atmospheric pressure occurs across the valve 72. When the valve 76 is then changed to a position disconnecting the discharge line 62 and connecting the line 74 to one of the normal operation, i.e., where no swellings exist on the slugs 8. If a swelling develops on a slug 8, the pressure at which motion of the row of'slugs 8 commences is greater than normal. Thus by periodic operation of the valve 76 in the manner described above, the existence of swellings on the slug 8 may bey constantly monitored.

It will be understood that only one embodiment of the invention is illustrated and described above. Persons skilled in the art will readily devise equivalents utilizing the teachings of the invention, land will adapt the inven-j tion to use under various conditions of service.

What is claimed is: p' 1. An apparatus for testing the expansion of *anitexj j pansible member within a tube comprisng opposed pistons cylinders 22 or 24, the pressure in the line 74, and-thus in the cylinder 22 or 24, builds up at a rate which is dependent upon the position of the valve 72 and the valve 84. These two valves may be adjusted to give adesired build-up time for the pressure, the valve 84 being used j for iine control.

In operation, the positioning of the valve 76 is cycled as follows: both cylinders 22and 24 are xed at atmospheric pressure byputting the valve 76 in 'its neutral position. The valve 76 is then placed in one of its other two positions. slugs `8 commences to move, as indicated visually, or by a motion-indicating device (not shown). 'I'he pressure, as indicated by the gauge 80, at which the row of slugs 8 commences to move may be recorded. Atmospheric pressure in the cylinders 22 and 24 and the line 74 is' then again restored by placing `the valve 76 in the neutral position. The valve 76 is then placed in the positionito connect the line 74 to the other of the cylinders 22 or 24. The pressure again builds up, and again the pressure at which the row of slugs 8 commences to move may be recorded. This operation may be continued at regular intervals. For example, a total cycle may take 20minutos, the rowof slugs 8 thus .being pushed every ten minutes. With such a. cycling itis found desirable to adjust the valve 72 and 84 so that pressure in the cylinders 22 and 24 builds up to the point where motion occurs in about 5 minutes in The pressure .then builds up until the row of projecting into opposite ends of said tube, hydraulic motor means for alternately `actuating said pistons to move said member back and forth within said tube, a source of pressure iluid connected to said means, and means for measuring the pressure of said uid.

2. An apparatus for testing the expansion of anex-` pansible member within a tube, comprising cylinders `at` opposite ends of saidtube, opposed pistons within respective cylinder projecting into opposite ends of said tube and acting upon said member, a supplyplinecontaining pressure fluid, valve means for alternately exhausting said line and directing flow of said fluid into respective cylinders, and means for measuring the pressuretin said line.

3. An apparatus for testing the expansion of an eX-,

pansible member withinra tube conveying fluid owing in one direction therethrough, said apparatus comprising opposed pistons projecting into opposite ends of said tube,

hydraulic motor means` for alternately actuating said pistons to move said member backl and forth within said` tube, `means for measuring the hydraulic pressure with-` in each of said motor means, and means for exhausting each of said motor means prior to actuation thereof, the. piston at the uid outlet end of said tube having a. greater diameter than the piston at the fluid inlet end thereof to equalize the pressure of said uid against said pistonsl 4. An apparatus for testing the expansion of an expansible member within a tube snugly engaging the mem.

ber, comprising cylinders at opposite ends of the tube,`

plungers projecting into opposite ends of the tube,.pistons within respective cylinders and operatively connected to said plungers for actuation thereof, said plungers being operatively connected to the member for moving the same back and forth Within the tube, a uid supply line, valve means for opening said line to communication iirst with one` of the cylinders, then to discharge, and then to the other of the cylinders, and means for measuring the pressure built up in said line when` the same is in' cornmunication with each of the cylinders.

References Cited in the le of this patent UNITED STATES PATENTS 1,137,821 White May 4, 1915 1,298,630 Schmidt Mar. 25, 1919 2,078,426 Sweet Apr. 27, 1937 2,084,683 Hewitt June 22,1937 2,281,871 Corby May 5, 1942 FOREIGN PATENTS 892,712 France ....-H. Ian. 13, 1944 

